Integrated diffuser grille for axial fan

ABSTRACT

An integrated diffuser grille for a coil unit includes a hub, a stack diffuser wall, a plurality of radial spokes extending between the hub and the stack diffuser wall, and a plurality of partial spokes extending inwardly from the stack diffuser wall. A radial length of the partial spokes is less than a radial length of the spokes. A plurality of circumferential elements is connected to the plurality of radial spokes between the hub and the stack diffuser wall. At least one circumferential element is connected to the plurality of partial spokes and at least one circumferential element has a non-uniform configuration about a circumference of the plurality of circumferential elements. A cross-section of the plurality of radial spokes has an airfoil-shape and at least one of a spoke pitch angle, camber angle, and chord of the airfoil-shape varies over a radial length of the plurality of spokes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/185,117 filed May 6, 2021, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

Exemplary embodiments of the disclosure relate generally to an air conditioning system, and more particularly, to an integrated diffuser grille suitable for use with a fan of an air conditioning system.

Conventional air conditioning units usually include an indoor unit for evaporation and heat absorption and an outdoor unit for condensation and heat dissipation. Such outdoor units or condensing units include grilles positioned over each fan to prevent foreign objects from being introduced into the flow path of the fan and serve as finger protection without impeding the fan performance. The grilles present in existing outdoor units or condensing units are typically wire grilles (made of metal). While existing wire grilles are suitable for their intended purpose, it is desirable to provide an alternate composite grille or guard without impeding the operational efficiency of the system or the compliancy with the UL standards required for such part.

BRIEF DESCRIPTION

Disclosed is an integrated diffuser grille for a coil unit including a hub, a stack diffuser wall, a plurality of radial spokes extending between the hub and the stack diffuser wall, and a plurality of partial spokes extending inwardly from the stack diffuser wall. A radial length of the partial spokes is less than a radial length of the spokes. A plurality of circumferential elements is connected to the plurality of radial spokes between the hub and the stack diffuser wall. At least one circumferential element is connected to the plurality of partial spokes and at least one circumferential element has a non-uniform configuration about a circumference of the plurality of circumferential elements. A cross-section of the plurality of radial spokes has an airfoil-shape and at least one of a spoke pitch angle, camber angle, and chord of the airfoil-shape varies over a radial length of the plurality of spokes.

In addition to one or more of the features described above, or as an alternative, in further embodiments the plurality of radial spokes and the plurality of partial spokes are configured to straighten an air flow as it flow across the plurality of radial spokes and the plurality of partial spokes.

In addition to one or more of the features described above, or as an alternative, in further embodiments a stacking line defined by a mid-chord of the airfoil-shape over the radial length of at least one of the plurality of radial spokes is a straight line.

In addition to one or more of the features described above, or as an alternative, in further embodiments each of the plurality of radial spokes includes a radially inner portion adjacent to the hub, a radially outer portion adjacent to the stack diffuser wall, and a radially middle portion disposed between the radially inner portion and the radially outer portion.

In addition to one or more of the features described above, or as an alternative, in further embodiments the radially inner portion extends from 0% to about 20% of the radial length, the radially middle portion extends from about 20% to about 70% of the radial length, and the radially outer portion extends from about 70% to 100% of the radial length.

In addition to one or more of the features described above, or as an alternative, in further embodiments the radially inner portion of at least one of the plurality of radial spokes has at least one of a spoke pitch angle that increases from about 45-55 degrees to about 60-65 degrees relative to a circumferential direction, a camber angle that decreases from about 15-25 degrees to about 0-5 degrees, and a chord that decreases from about 80%-85% to about 70%-75% relative to the chord at a tip section.

In addition to one or more of the features described above, or as an alternative, in further embodiments the radially outer portion of at least one of the plurality of radial spokes has at least one of a spoke pitch angle that decreases from about 70-80 degrees to about 30-50 degrees relative to a circumferential direction, a camber angle that increases from about 0-5 degrees to about 15-25 degrees, and a chord that increases from about 65%-70% to 100% relative to the chord at a tip section.

In addition to one or more of the features described above, or as an alternative, in further embodiments the radially middle portion of at least one of the plurality of radial spokes has at least one of a spoke pitch angle that increases from about 60-65 degrees to about 70-80 degrees relative to a circumferential direction, a camber angle that is constant between about 0-5 degrees, and a chord that decreases from about 70%-75% to about 65%-70% relative to the chord at a tip section.

In addition to one or more of the features described above, or as an alternative, in further embodiments each of the plurality of partial spokes has an airfoil-shape and a configuration of the plurality of partial spokes is substantially identical to a configuration of the plurality of radial spokes at a same radial position.

In addition to one or more of the features described above, or as an alternative, in further embodiments the hub, stack diffuser wall, plurality of radial spokes, plurality of partial spokes, and plurality of circumferential elements are integrally formed as a single unitary structure, the single unitary structure being formed from a non-metal material.

In addition to one or more of the features described above, or as an alternative, in further embodiments the single unitary structure is formed from a plastic material.

In addition to one or more of the features described above, or as an alternative, in further embodiments the plurality of circumferential elements have an upstream side and a downstream side, and the upstream side of the at least one circumferential element has a non-uniform contour.

In addition to one or more of the features described above, or as an alternative, in further embodiments a depth increases in a direction toward the upstream side of the at least one circumferential element at a location adjacent to an interface with each of the plurality of radial spokes.

In addition to one or more of the features described above, or as an alternative, in further embodiments the radial length of the plurality of partial spokes is less than or equal to about 40% of the radial length of the plurality of radial spokes.

In addition to one or more of the features described above, or as an alternative, in further embodiments comprising a plurality of features integrally formed with the stack diffuser wall.

In addition to one or more of the features described above, or as an alternative, in further embodiments the plurality of features are radially aligned with the plurality of radial spokes and the plurality of partial spokes.

In addition to one or more of the features described above, or as an alternative, in further embodiments the plurality of features are arranged in groups, the groups being spaced about a periphery of the outer wall.

In addition to one or more of the features described above, or as an alternative, in further embodiments the integrated diffuser grille is part of a top cover assembly of an air chiller unit of an air conditioning system.

In addition to one or more of the features described above, or as an alternative, in further embodiments the top cover assembly further comprises a fan assembly, the integrated diffuser grille being positioned in overlapping arrangement with the fan assembly to restrict access to the fan assembly.

In addition to one or more of the features described above, or as an alternative, in further embodiments the integrated diffuser grille is positioned downstream of the fan assembly relative to an airflow through the fan assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 is a perspective view of an exemplary air-cooled chiller unit according to an embodiment;

FIG. 2A is a front view of a coil unit of the air-cooled chiller unit of FIG. 1 according to an embodiment;

FIG. 2B is a top view of the coil unit of FIG. 2A according to an embodiment;

FIG. 3 is a perspective view of an integrated diffuser grille for a coil unit according to an embodiment;

FIG. 4 is a top plan view of the integrated diffuser grille of FIG. 3 according to an embodiment;

FIG. 5 is a rear view of the integrated diffuser grille of FIG. 3 according to an embodiment;

FIG. 6 is a cross-sectional side view of the integrated diffuser grille of FIG. 3 according to an embodiment;

FIG. 7 is a top view of a portion of the integrated diffuser grille of FIG. 3 according to an embodiment;

FIGS. 8A-8C are cross-sectional views of a radial spoke of the integrated diffuser grille of FIG. 7 taken at various locations over the span of the spoke according to an embodiment;

FIG. 9 is a detailed perspective view of an exterior surface of an outer wall of the integrated diffuser grille according to an embodiment; and

FIG. 10 is a detailed perspective view of a rear of the integrated diffuser grille according to an embodiment.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

Referring now to FIG. 1, an exemplary air-cooled chiller unit 10 of an air conditioning system is illustrated. The air-cooled chiller unit 10 may include a single coil unit 20, or alternatively, a plurality of coil units 20 arranged in a stacked configuration. With reference now to FIGS. 2A and 2B, each coil unit 20 has a housing including a base or base pan 22 having a generally rectangular planform. However, embodiments where the planform of the base pan 22 is another configuration, such as square, cylindrical, or another shape for example, are also within the scope of the disclosure.

The base pan 22 supports the remainder of the components of the coil unit 20. As shown, a heat exchanger assembly 24 is arranged within the base pan 22. In the illustrated, non-limiting embodiment, the heat exchanger assembly 24 includes two heat exchanger coils oriented in a V or A-shape. However, a heat exchanger assembly having another shape, such as a W-shape for example, is also contemplated herein. Further, embodiments where the heat exchanger assembly 24 wraps about one, two, three, or four sides and/or one or more corners of the footprint of the base pan 22 between two headers are also within the scope of the disclosure. However, in such embodiments, the planform of the heat exchanger assembly 24 need not match the planform of the base pan 22. A compressor 26, fluidly coupled to the heat exchanger 24, is positioned within the interior of the heat exchanger 24 and is configured to pump refrigerant through a vapor compression cycle.

The base pan 22 forms a lower portion of the housing, and a top cover assembly 30 forms an upper portion of the housing. Along the lateral perimeter, the housing may include one or more louvered panels 28, corner posts (not shown), or another structural member to connect the base pan 22 and the top cover assembly 30. The top cover assembly 30 includes at least one fan assembly 32 and a grille or fan guard 34 associated with each fan assembly 32. It will be appreciated that the grilles or fan guards 34 illustrated in FIGS. 1, 2A, and 2B are of the configuration commonly used today (i.e., wire grilles made of metal). Although two fan assemblies 32 are shown in the illustrated, non-limiting embodiment, it should be understood that embodiments of a coil unit having a single fan assembly, or more than two fan assemblies are contemplated herein. Each fan assembly 32 is configured to draw ambient air radially inward and across the heat exchanger assembly 24. The heated air downstream from the heat exchanger assembly 24 is then drawn axially across the one or more fan assemblies 32 and discharged upwardly through the openings in the fan guard 34, to be described in more detail below. Although a coil unit 20 having a specific configuration is illustrated and described herein, it should be understood that a coil unit 20 having another configuration is also within the scope of the disclosure.

With reference now to FIG. 2B, an example of a top cover assembly 30 is illustrated in more detail. As shown, a fan assembly 32 of the top cover assembly 30 includes a housing 36 and a fan rotor or impeller 38 located within the housing 36. The fan rotor 38 generally includes a plurality of fan blades 40 extending radially outward from a hub 42. The distal ends 44 of the fan blades 40 may be connected to a shroud, or alternatively, the distal ends 44 of the fan blades 40 may define an orifice or throat (not shown) between the fan blades 40 and an adjacent surface of the housing 36. A motor 48 operably coupled to the fan assembly 32, such as via a shaft or another coupling means, such as a belt, rope, or chain for example, may be used to operate the fan assembly 32 by rotating the fan rotor 38 about a fan axis X (see FIG. 2A). The motor 48 may be oriented generally vertically, such that an axis of rotation (not shown) of the motor 48 is arranged parallel to or coaxial with the fan axis X. However, it should be understood that a fan assembly 32 having another configuration, or another type of fans, such as a mixed flow fan for example, are within the scope of the present disclosure.

With reference now to FIGS. 3-10, an integrated diffuser grille 34 (i.e., to replace the traditional wire grille used today, shown in FIGS. 1, 2A, and 2B) is illustrated. It will be appreciated that the integrated diffuser grille 34 may be referred to herein as a grille 34. As shown in FIG. 3, the grille 34 includes a hub 50, a stack diffuser wall or outer wall 52, and a plurality of spokes 54 extending radially between and connected to an exterior of the hub 50 and an interior of the stack diffuser wall 52. The stack diffuser wall 52 may be able to be positioned in overlapping arrangement with the housing 36 of the fan assembly 32 (shown in FIG. 2A), such as an exterior surface thereof for example. In the illustrated, non-limiting embodiment, the grille 34 includes sixteen radial spokes 54 spaced equidistantly about the periphery of the hub 50. However, it should be understood that embodiments having any number of spokes 54 and/or embodiments where the spokes 54 are non-uniformly spaced are also contemplated herein. Further, the plurality of spokes 54 may be substantially identical, or alternatively, a configuration of the spokes 54 may vary about the periphery of the hub 50.

As best shown in FIGS. 8A-8C, a cross-section of each of the spokes 54 when taken in a plane oriented generally parallel to the fan axis X has an airfoil-shape. The term “airfoil shape” as known in the art and used herein refers to a shape having a generally curved leading edge, a curved or pointed trailing edge, and a curved upper and lower surface extending between and connecting the leading edge and the trailing edge. The spokes 54 may have a leading edge facing the upstream fan assembly 32 and a downstream edge facing outwardly towards the ambient atmosphere surrounding the grille 34. A mid-chord point is defined at a center of an imaginary straight line extending between the leading edge and the trailing edge (also known as a chord). A stacking line of each spoke 54 is defined by the mid-chord point of the airfoil shaped cross-section taken over the radial span of the spoke 54. In an embodiment, the stacking line of at least one of the plurality of spokes 54 is substantially straight. However, embodiments where the stacking line of one or more of the spokes 54 has another configuration, such as a non-linear configuration for example, are also within the scope of the disclosure.

In embodiments where the fan assembly 32 is configured as an axial flow fan, the airflow A moving through the fan assembly 32 towards the grille 34 generally has both an axial component, a radial component, and a tangential component. In an embodiment, the plurality of spokes 54 are configured as outlet guide vanes. Accordingly, the configuration of the radial spokes 54 may be selected to straighten the flow exiting from the fan assembly 32, thereby transforming swirl kinetic energy in the airflow A into static pressure rises across the spokes 54. In such embodiments, the spokes 54 may include lean or sweep in the circumferential or axial directions. Parameters of the spokes 54 that may be controlled to diffuse or straighten the air flow A include, but are not limited to spoke pitch angle, chamber angle, and chord.

The configuration of each spoke 54 may vary over the radial length or span of the spoke 54 to compensate for the conditions of the airflow A in that region. For example, each spoke 54 may include a radially inner portion extending from the hub (0%) to about 20% of the span, a radially middle portion extending between about 20% of the span and about 70% of the span, and a radially outer portion extending from about 70% to 100% of the span. An example of a cross-section of a radially inner portion of a spoke 54 is shown in FIG. 8A. In an embodiment, the air flow A output from the fan rotor 38 may have a high spanwise swirl adjacent the hub 42, and therefore the radially inner portion of the spokes 54 aligned with the fan rotor 38 surrounding the hub 42. In such embodiments, the spoke pitch angle of the radially inner portion of at least one of the plurality of spokes 54 measured relative to the circumferential direction may gradually increase by about ten degrees or more, such as from about 45-55 degrees to about 60-65 degrees for example, relative to the circumferential direction. Alternatively, or in addition, the camber angle of the radially inner portion of at least one of the plurality of spokes 54 may gradually decrease by at least about 10 degrees, such as from about 15-25 degrees to about 0-5 degrees for example. Further, the chord of the radially inner portion may gradually decrease by about 10-15%, such as from about 80%-85% to about 70%-75% of the chord at a tip section of the spoke 54. As used herein the phrase “the tip section” refers to the distal end of the spoke 54, at the interface between the spoke 54 and the outer wall 52.

The radially middle portion of at least one of the spokes 54, as shown in FIG. 7C, may have one or more of a spoke pitch angle that gradually increases by about ten degrees or more, such as from about 60-65 degrees to about 70-80 degrees relative to the circumferential direction, a constant camber angle between about 0-5 degrees, and a decrease in chord by about 5% or more, such as from about 70%-75% to about 65%-70% of the chord at the tip section.

The air flow A output from the fan rotor 38 may have a high swirl adjacent to the distal ends 44 of the fan blades 40. To compensate for this flow, the radially outer portion of one or more of the spokes 54, see FIG. 8B, which is axially aligned with the distal ends 44 of the fan blades 40, may have a sharp decrease in spoke pitch angle, such as a decrease of about 20 degrees or more, such as from about 70-80 degrees to about 30-50 degrees for example, relative to the circumferential direction. Alternatively, or in addition, the camber angle of the radially outer portion of at least one of the spokes 54 may sharply increase, such as by at least about 10 degrees for example, from about 0-5 degrees to about 15-25 degrees and/or the chord of the radially outer portion of at least one of the spokes 54 may sharply increase by at least about 20%, such as from about 65%-70% to 100% of the chord at the tip section.

In the illustrated, non-limiting embodiment, the grille 34 additionally includes a plurality of partial spokes 56 extending inwardly from the outer wall 52 and arranged between pairs of adjacent spokes 54. Although the partial spokes 56 are shown equidistantly spaced between each pair of adjacent spokes 54, embodiments where one or more of the partial spokes 56 is arranged at a non-central location between a pair of spokes 54 are also contemplated herein. A radial length of the partial spokes 56 is less than a radial length of the spokes 54. In an embodiment, the radial length of the partial spokes 56 is less than 50% of the radial length of the spokes 54, and further may be less than 40%, less than 30%, or even less than 20% of the radial length of the spokes 54.

Because the airflow A provided to partial spokes 56 has the same flow conditions as the flow provided to a corresponding portion of the spokes 54, in an embodiment, a configuration of the partial spokes 56 is substantially identical to a configuration of the spokes at the same radial location (see FIG. 8B). For example, the spoke pitch angle, chord, and camber angle of the partial spokes 56 may be the same as the spoke pitch angle, chord, and camber angle of the spoke 54 at the same spanwise location.

With reference again to FIG. 3 and further reference to FIG. 9, to enhance the structural rigidity of the outer wall 52, a plurality of structural features 60, such as ribs or tabs for example, may be arranged about the periphery of the exterior surface 61 of the outer wall 52. The features 60 may be separate components attached to the outer wall 52 or may be integrally formed as a part of the outer wall 52. The configuration of the structural features 60 may be selected based on the forces and/or stresses experienced at the outer wall 52. The structural features 60 may be individual features, or alternatively, may be formed in groups as shown in the FIGS. In embodiments where the features 60 are clustered in groups, the features 60 within each group may be substantially identical or may vary. The individual features 60 or groups of features 60 may extend about only a portion, or alternatively, the entire of periphery of the outer wall 52. Further, the features 60 or groups of features 60 may be continuously arranged or may be spaced at intervals about all or a portion of the periphery. In an embodiment, each feature 60 or group of features 60 is radially aligned with one of the plurality of spokes 54 or one of the plurality of partial spokes 56, respectively.

The grille 34 may additionally include one or more elements 62 extending circumferentially about the hub 50, between the hub 50 and the outer wall 52. In the illustrated, non-limiting embodiment, the grille 34 includes a plurality of concentrically mounted circumferential elements 62 spaced equidistantly from one another and between the hub 50 and the outer wall 52. However, embodiments where the circumferential elements 62 are not equidistantly spaced or where a center of one or more of the circumferential elements 62 is offset from the fan axis X are also within the scope of the disclosure. A plurality of openings 64 are defined between adjacent circumferential elements 62, radial spokes 54, and partial spokes 56. In an embodiment, the size of the plurality of openings 64 is selected to prevent the introduction of foreign objects or a finger into the fan assembly 32 via the grille 34. However, it should be noted that the size of the openings 64 defined at least partially by the partial spokes 56 are smaller than the openings 64 defined between adjacent radial spokes 54 and circumferential elements 62.

As shown, each of the circumferential elements 62 may be connected to each of the plurality of radial spokes 54. Further, at least a portion of the circumferential elements 62 may be configured to overlap with the partial spokes 56 and may be similarly connected to each of the partial spokes 56. In an embodiment, the hub 50, stack diffuser outer wall 52, spokes 54, partial spokes 56, and circumferential elements 62 are integrally formed as a single unitary component. In such embodiments, the grille 34 may be manufactured via any suitable process, including but not limited to injection molding or additive manufacturing for example. In an embodiment, the grille 34 is formed from a non-metal material, such as plastic or composite for example. By using a plastic material, the potential for degradation, such as the formation of rust as a result of exposure to the elements (for example rain) is eliminated. However, embodiments where the grille 34 is formed from a metal material are also within the scope of the disclosure.

In an embodiment, a configuration of one or more of the circumferential elements 62 varies or is non-uniform about its circumference. For example, as best shown in FIG. 9, a thickness of the circumferential elements 62, measured parallel to the fan axis X, may be non-uniform to reduce the aerodynamic losses as the airflow passes over the circumferential elements 62. In the illustrated, non-limiting embodiment, the depth of one or more of the circumferential elements 62 directly adjacent a radial spoke 54 or partial spoke 56 is increased relative to a portion of a circumferential element 62 arranged centrally between two radial spokes 54 or centrally between a partial spoke 56 and a radial spoke 54. As shown, the thickness may taper from a first depth at a central portion of the circumferential element 62 to a second depth adjacent the spokes 54 and partial spokes 56. Further, in an embodiment, this tapered depth is present at the upstream end of the circumferential elements 62, facing the fan assembly 32. Accordingly, the downstream end of each of the circumferential elements 62 may be substantially uniform about its periphery and arranged within a plane. However, other configurations of the circumferential elements 62 are contemplated herein.

As illustrated and described above, the grille 34 may be suitable for use with a coil unit 20. In certain instances, the grille 34 may be configured to satisfy all UL compliance requirements for outdoor fan grilles. For example, the grille may be formed from a UL approved material, satisfy UL finger protection requirements, and may support a structural load of 200 pounds over a 6 inches diameter circle. Further, the performance of the grille 34 may be on par with (or better than) existing wire grilles and may provide a suitable replacement option for existing systems without negatively impacting the aerodynamic performance of the fan assembly or overall system efficiency.

The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.

While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims. 

What is claimed is:
 1. An integrated diffuser grille for a coil unit comprising: a hub; a stack diffuser wall; a plurality of radial spokes extending between the hub and the stack diffuser wall; a plurality of partial spokes extending inwardly from the stack diffuser wall, wherein a radial length of the plurality of partial spokes is less than a radial length of the plurality of spokes; and a plurality of circumferential elements arranged between the hub and the stack diffuser wall, the plurality of circumferential elements being connected to the plurality of radial spokes, at least one circumferential element of the plurality of circumferential elements being connected to the plurality of partial spokes, at least one circumferential element of the plurality of circumferential elements having a non-uniform configuration about a circumference of the plurality of circumferential elements; wherein a cross-section of the plurality of radial spokes has an airfoil-shape and wherein at least one of a spoke pitch angle, camber angle, and chord of the airfoil-shape varies over a radial length of the plurality of spokes
 2. The integrated diffuser grille according to claim 1, wherein the plurality of radial spokes and the plurality of partial spokes are configured to straighten an air flow as it flow across the plurality of radial spokes and the plurality of partial spokes.
 3. The integrated diffuser grille according to claim 1, wherein a stacking line defined by a mid-chord of the airfoil-shape over the radial length of at least one of the plurality of radial spokes is a straight line.
 4. The integrated diffuser grille according to claim 1, wherein each of the plurality of radial spokes includes a radially inner portion adjacent to the hub, a radially outer portion adjacent to the stack diffuser wall, and a radially middle portion disposed between the radially inner portion and the radially outer portion.
 5. The integrated diffuser grille according to claim 4, wherein the radially inner portion extends from 0% to about 20% of the radial length, the radially middle portion extends from about 20% to about 70% of the radial length, and the radially outer portion extends from about 70% to 100% of the radial length.
 6. The integrated diffuser grille according to claim 4, wherein the radially inner portion of at least one of the plurality of radial spokes has at least one of a spoke pitch angle that increases from about 45-55 degrees to about 60-65 degrees relative to a circumferential direction, a camber angle that decreases from about 15-25 degrees to about 0-5 degrees, and a chord that decreases from about 80%-85% to about 70%-75% relative to the chord at a tip section.
 7. The integrated diffuser grille according to claim 4, wherein the radially outer portion of at least one of the plurality of radial spokes has at least one of a spoke pitch angle that decreases from about 70-80 degrees to about 30-50 degrees relative to a circumferential direction, a camber angle that increases from about 0-5 degrees to about 15-25 degrees, and a chord that increases from about 65%-70% to 100% relative to the chord at a tip section.
 8. The integrated diffuser grille according to claim 4, wherein the radially middle portion of at least one of the plurality of radial spokes has at least one of a spoke pitch angle that increases from about 60-65 degrees to about 70-80 degrees relative to a circumferential direction, a camber angle that is constant between about 0-5 degrees, and a chord that decreases from about 70%-75% to about 65%-70% relative to the chord at a tip section.
 9. The integrated diffuser grille according to claim 1, wherein each of the plurality of partial spokes has an airfoil-shape and a configuration of the plurality of partial spokes is substantially identical to a configuration of the plurality of radial spokes at a same radial position.
 10. The integrated diffuser grille of claim 1, wherein the hub, stack diffuser wall, plurality of radial spokes, plurality of partial spokes, and plurality of circumferential elements are integrally formed as a single unitary structure, the single unitary structure being formed from a non-metal material.
 11. The integrated diffuser grille according to claim 10, wherein the single unitary structure is formed from a plastic material.
 12. The integrated diffuser grille according to claim 1, wherein the plurality of circumferential elements have an upstream side and a downstream side, and the upstream side of the at least one circumferential element has a non-uniform contour.
 13. The integrated diffuser grille according to claim 12, wherein a depth increases in a direction toward the upstream side of the at least one circumferential element at a location adjacent to an interface with each of the plurality of radial spokes.
 14. The integrated diffuser grille according to claim 1, wherein the radial length of the plurality of partial spokes is less than or equal to about 40% of the radial length of the plurality of radial spokes.
 15. The integrated diffuser grille according to claim 1, further comprising a plurality of features integrally formed with the stack diffuser wall.
 16. The integrated diffuser grille according to claim 15, wherein the plurality of features are radially aligned with the plurality of radial spokes and the plurality of partial spokes.
 17. The integrated diffuser grille according to claim 15, wherein the plurality of features are arranged in groups, the groups being spaced about a periphery of the outer wall.
 18. The integrated diffuser grille according to claim 1, wherein the integrated diffuser grille is part of a top cover assembly of an air chiller unit of an air conditioning system.
 19. The integrated diffuser grille according to claim 18, wherein the top cover assembly further comprises a fan assembly, the integrated diffuser grille being positioned in overlapping arrangement with the fan assembly to restrict access to the fan assembly.
 20. The integrated diffuser grille according to claim 18, wherein the integrated diffuser grille is positioned downstream of the fan assembly relative to an airflow through the fan assembly. 